Only try to install vundle if it's not installed

Prevents error on re-running ./install.sh:

    fatal: destination path '~/.vim/bundle/vundle' already exists and is
    not an empty directory.

https://github.com/thoughtbot/dotfiles/issues/195
Use bin/stubs when running `binstubs`

Fixes gems and old projects on Rails 3 that can't use `bin/`.
Remove old Rubygems aliases

I stopped using these.
Add `git contrib`

Finds contributors for a given range
Restore snippets, indentation config
Fix gitignore for binstubs, foreman
Don't profile specs, allow projects to specificy spec order

* Profile was annoying, not useful on most runs
* Random specs break projects that don't expect it
Fix nocompatible wiping out certain settings

Doing a `set nocompatible` in `.vimrc.bundles` restores some settings to
their defaults.
Configure faster ctrlp, snippets, greplace
Fix spring config

* Spring doesn't generate bin/spring anymore
Use zsh-completions

Installed using homebrew
Remove client project settings
Store more history and share it between settings